Re: bugreport: "git checkout -B" allows checking out one branch across multiple worktrees

From: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Date: Jan 16, 2023, 00:11 UTC
Message-ID: <20230116001144.dt76xk6hkwn45klz@Carlos-MacBook-Pro-2.local>
In-Reply-To: <CAA3Q-aaO=vcZd9VLFr8UP-g06be80eUWN_GjygfyGkYmrLx9yQ@mail.gmail.com>

On Sat, Jan 14, 2023 at 06:45:34PM +0900, Jinwook Jeong wrote:

Show 8 quoted lines

> What did you do before the bug happened? (Steps to reproduce your issue)
> 
> 1. `cd` into any git repo that has at least one commit.
> 2. Identify the current branch, say main
> 3. $ git branch foo # a new branch
> 4. $ git worktree add ../new_worktree foo
> 5. $ cd ../new_worktree
> 6. $ git checkout -B master HEAD

Was your intention to get this worktree's content back to what is in master's HEAD?, then the command should had been

$ git reset --hard master

The documentation might be confusing, but you most likely do NOT want to use -B unless you want to force things, but the lowercase version `-b`

Show 13 quoted lines

> Anything else you want to add:
> 
> https://www.git-scm.com/docs/git-checkout#Documentation/git-checkout.txt-emgitcheckoutem-b-Bltnew-branchgtltstart-pointgt
> 
> According to the documentation, "git checkout -B BRANCH START" is the
> transactionally equivalent of:
> 
>   git branch -f BRANCH START
>   git checkout BRANCH
> 
> When I ran the first command in place of the step 6 of the above
> reproducing procedure, git refused to carry on;
> I suppose that this is the intended behavior for "git checkout -B".

I think you are correct, and this is therefore a bug, but there is also a reason why `--force` allows doing dangerous things and I am not sure if it might apply here.

Carlo